Contact probe and probe unit

ABSTRACT

A contact probe is conductive and capable of expanding/contracting along an axial line direction. The contact probe includes: a first contact member configured to contact one contact target; a second contact member configured to contact another contact target, and to house at least a portion of the first contact member; and a spring member configured to couple the first contact member and the second contact member in a manner capable of expansion/contraction with both end parts of the spring member. The spring member is wound in a helical shape, and at least a diameter of an outer circumference in one of the end parts held by the second contact member is larger than diameters of other portions. A diameter of an inner circumference of an end part of the second contact member on a side housing the first contact member is equal to or larger than a maximum diameter of the first contact member.

FIELD

The present invention relates to a contact probe and a probe unit thatare used for conductivity test or performance characteristic test oninspected test target such as a semiconductor integrated circuit orliquid crystal panel.

BACKGROUND

Conventionally, at the time of conductivity test or performancecharacteristic test on inspected test target such as a semiconductorintegrated circuit or liquid crystal panel, a probe unit for housing aplurality of contact probes has been used to realize an electricalconnection between the test target and a signal processing device foroutputting a test signal. With regard to probe units, a technique ofallowing application to a high-integrated or miniaturized test target bynarrowing a pitch between contact probes has been developed inaccordance with progress of high integration or miniaturization ofsemiconductor integrated circuits and liquid crystal panels of recentyears.

As the contact probes mentioned above, a contact probe including a pipemember, a plunger that extends from the pipe member in a manner capableof freely moving back and forth, and a spring member that is providedinside the pipe member for biasing the plunger, has been known (forexample, see Patent Literature 1). In Patent Literature 1, the plungeris prevented from falling off by swaging an end part of the pipe memberfrom which the plunger extends.

CITATION LIST Patent Literature

Patent Literature 1: Japanese Patent No. 5083430

SUMMARY Technical Problem

However, in the conventional contact probe disclosed in PatentLiterature 1, when the diameter of the pipe member is reduced tominiaturize the contact probe, strength of the pipe member is degraded.There has been a problem in that, due to degradation of strength of thepipe member, the end part cannot be swaged, and the contact probe havinga reduced diameter cannot be obtained.

The present invention has been made in view of the foregoing, and anobjective of the present invention is to provide a contact probe and aprobe unit that can achieve a reduced diameter in a configuration usinga pipe member.

Solution to Problem

To solve the above-described problem and achieve the object, a contactprobe according to the present invention that is conductive and capableof expanding/contracting along an axial line direction includes: a firstcontact member configured to contact one contact target; a secondcontact member configured to contact another contact target, and tohouse at least a portion of the first contact member; and a springmember configured to couple the first contact member and the secondcontact member in a manner capable of expansion/contraction with bothend parts of the spring member, wherein the spring member is wound in ahelical shape, and at least a diameter of an outer circumference in oneof the end parts held by the second contact member is larger thandiameters of other portions.

Moreover, in the above-described contact probe according to the presentinvention, the first contact member includes: a first tip partconfigured to contact the one contact target; a first flange partprovided at a base end of the first tip part; and a boss part configuredto couple with the spring member by fitting into the spring member, andthe second contact member includes: a second tip part configured tocontact the other contact target, a cylindrical part extending from thesecond tip part and having a cylindrical shape with an innercircumference having a uniform diameter, cylindrical part housing atleast a portion of the spring member; and a second flange part providedin an outer circumference of the cylindrical part.

Moreover, in the above-described contact probe according to the presentinvention, a length of the spring member in a natural state thereof inthe axial line direction is smaller than a length of the cylindricalpart in the axial line direction.

Moreover, in the above-described contact probe according to the presentinvention, a length of the spring member in a natural state thereof inthe axial line direction is larger than a length of the cylindrical partin the axial line direction.

Moreover, the above-described contact probe according to the presentinvention further includes a sleeve into which the first flange part isfit, an outer surface of the sleeve slidably contacting the cylindricalpart.

Moreover, in the above-described contact probe according to the presentinvention, the spring member includes: a rough wound part wound with apreviously set gap, an inner circumference of the rough wound partcontacting the first contact member; and a dense wound part extendingfrom the rough wound part, an outer circumference of the dense partcontacting the cylindrical part, and a diameter of the dense wound partis larger than a diameter of the rough wound part.

Moreover, in the above-described contact probe according to the presentinvention, the first contact member includes: a first tip partconfigured to contact the one contact target; a first cylindrical partextending from the first tip part in a cylindrical shape; and a firstflange part provided in an outer circumference of the first cylindricalpart, the second contact member includes: a second tip part configuredto contact the other contact target; a second cylindrical part extendingfrom the second tip part and having a cylindrical shape with an innercircumference having a uniform diameter; and a second flange partprovided in an outer circumference of the second cylindrical part, andthe spring member is positioned in a hollow space formed with the firstand the second cylindrical parts.

Moreover, in the above-described contact probe according to the presentinvention, the spring member includes: a first dense wound part, anouter circumference of the first dense wound part contacting the firstcylindrical part; a rough wound part wound with a previously set gap,the rough wound part extending from the first dense wound part; and asecond dense wound part, an outer circumference that of the second densewound part contacting the second cylindrical part, and the second densewound part being provided at an end part of the rough wound part on anopposite side of the first dense wound part, a diameter of the firstdense wound part is smaller than a diameter of the second dense woundpart, and a diameter of the rough wound part is smaller than thediameter of the first dense wound part.

Moreover, in the above-described contact probe according to the presentinvention, the end part of the first flange part on an opposite side ofa side continuous to the first contact member has a tapered shape.

Moreover, a probe unit according to the present invention includes:contact probes, each of which is conductive, and capable ofexpanding/contracting along an axial line direction, each of the contactprobes including: a first contact member configured to contact onecontact target; a second contact member configured to contact anothercontact target, and to house at least a portion of the first contactmember; and a spring member wound in a helical shape and configured tocouple the first contact member and the second contact member in amanner capable of expansion/contraction with both end parts of thespring member, wherein a diameter of an outer circumference in the endpart held by at least the second contact member being larger thandiameters of other portions; and a probe holder including holder holesconfigured to hold the respective contact probes.

Moreover, in the above-described probe unit according to the presentinvention, the first contact member includes a flange part having amaximum diameter of the first contact member, and when the contact probeis held by the probe holder, at least a portion of the flange part ispositioned inside the second contact member.

Moreover, in the above-described probe unit according to the presentinvention, the first contact member includes a flange part having amaximum diameter of the first contact member, and when the contact probeis held by the probe holder, the flange part is positioned outside thesecond contact member.

Moreover, in the above-described probe unit according to the presentinvention, the probe holder is made of a single plate.

Moreover, in the above-described probe unit according to the presentinvention, the second contact member includes: a tip part configured tocontact the other contact target; a cylindrical part extending from thetip part and having a cylindrical shape with an inner circumferencehaving a uniform diameter; and a flange part provided in an outercircumference of the cylindrical part, and a slit extending from the endpart of the cylindrical part on an opposite side of the tip part isformed in the cylindrical part.

Advantageous Effects of Invention

A contact probe according to the present invention exerts an effect thata reduced diameter can be achieved in a configuration using a pipemember.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a perspective view illustrating a configuration of a probeunit according to a first embodiment of the present invention.

FIG. 2 is a partial sectional view illustrating a configuration of achief part of the probe unit according to the first embodiment of thepresent invention.

FIG. 3 is a partial sectional view illustrating a configuration of acontact probe according to the first embodiment of the presentinvention.

FIG. 4A is a figure explaining a contracted mode of the contact probeaccording to the first embodiment of the present invention.

FIG. 4B is a figure explaining the contracted mode of the contact probeaccording to the first embodiment of the present invention.

FIG. 5 is a sectional view illustrating a configuration of a chief partof a contact probe according to a first modification of the firstembodiment of the present invention.

FIG. 6 is a partial sectional view illustrating a configuration of achief part of a probe unit according to a second modification of thefirst embodiment of the present invention.

FIG. 7 is a partial sectional view illustrating a configuration of acontact probe according to the second modification of the firstembodiment of the present invention.

FIG. 8 is a partial sectional view illustrating a configuration of achief part of a probe unit according to a third modification of thefirst embodiment of the present invention.

FIG. 9 is a partial sectional view illustrating a configuration of achief part of a probe unit according to a fourth modification of thefirst embodiment of the present invention.

FIG. 10 is a partial sectional view illustrating a configuration of achief part of a probe unit according to a fifth modification of thefirst embodiment of the present invention.

FIG. 11 is a partial sectional view illustrating a configuration of acontact probe according to a sixth modification of the first embodimentof the present invention.

FIG. 12 is a partial sectional view illustrating a configuration of acontact probe according to a seventh modification of the firstembodiment of the present invention.

FIG. 13 is a partial sectional view illustrating a configuration of achief part of a probe unit according to a second embodiment of thepresent invention.

DESCRIPTION OF EMBODIMENTS

Embodiments of the present invention will now be described in detailwith reference to the attached drawings. The present invention is notlimited to the following embodiments. In addition, each of the figuresreferred to in the following descriptions merely schematicallyillustrates the shapes, sizes, and positional relations in a degree thatallows understanding of the contents of the present invention.Accordingly, the present invention is not limited only to the shapes,sizes, and positional relations exemplified in each of the figures.

First Embodiment

FIG. 1 is a perspective view illustrating a configuration of a probeunit according to a first embodiment of the present invention. A probeunit 1 illustrated in FIG. 1 is a device that is used when performingelectrical property test on a semiconductor integrated circuit 100 thatis inspected test target, and is a device for electrically connectingthe semiconductor integrated circuit 100 and a circuit board 200 thatoutputs a test signal to the semiconductor integrated circuit 100.

The probe unit 1 includes a conductive contact probe 2 (hereinaftersimply referred to as the “probe 2”) that contacts, at both ends in thelongitudinal direction, the semiconductor integrated circuit 100 and thecircuit board 200, which are two contact targets different from eachother, a probe holder 3 that houses and holds a plurality of the probes2 according to a predetermined pattern, and a holder member 4 that isprovided in the surrounding of the probe holder 3 for suppressingoccurrence of dislocation of the semiconductor integrated circuit 100contacting the probes 2 at the time of test. For example, a distance(pitch) between adjacent probes 2 is 0.8 mm.

FIG. 2 is a partial sectional view illustrating a configuration of achief part of the probe unit according to the first embodiment of thepresent invention, and is a figure illustrating a detailed configurationof the probe 2 housed in the probe holder 3. FIG. 3 is a partialsectional view illustrating a configuration of a contact probe accordingto the first embodiment of the resent invention. The probe 2 illustratedin FIG. 3 is in a state in which a load other than gravity force is notapplied from the outside. The probe 2 illustrated in FIG. 2 and FIG. 3is formed with a conductive material, and it includes a plunger 21 thatcontacts a connection electrode of the semiconductor integrated circuit100 when performing test on the semiconductor integrated circuit 100, apipe member 22 that contacts an electrode of the circuit board 200having a test circuit, and a spring member 23 that couples the plunger21 and the pipe member 22 in a manner capable of expansion andcontraction with both end parts. The plunger 21, the pipe member 22, andthe spring member 23 constituting the probe 2 have the same axial line.Specifically, with regard to the plunger 21, the pipe member 22, and thespring member 23, each of the central axes thereof matches an axial lineN (see FIG. 2). The match mentioned here includes a certain degree ofinclinations. At the time of contact of the semiconductor integratedcircuit 100, the probe 2 reduces the impact on the connection electrodeof the semiconductor integrated circuit 100 with expansion/contractionof the spring member 23 in the axial line N direction, and applies aload to the semiconductor integrated circuit 100 and the circuit board200.

The plunger 21 includes a tip part 21 a having a crown shape, a flangepart 21 b having a larger diameter than the diameter of the tip part 21a, a boss part 21 c into which an end part of the spring member 23 ispress-fitted, that extends to the opposite side to the tip part 21 awith respect to the flange part 21 b and has a smaller diameter than theflange part 21 b does, and a base end part 21 d that extends to theopposite side to the flange part 21 b with respect to the boss part 21 cand has a diameter slightly smaller than the diameter of the boss part21 c. The plunger 21 is capable of moving in the axial line directionwith expansion/contraction action of the spring member 23, and is biasedin the direction of the semiconductor integrated circuit 100 withelastic force of the spring member 23, thereby contacting the electrodeof the semiconductor integrated circuit 100. The diameter mentioned hererefers to the diameter of the circle in a cross-section surface having aflat surface as the cutting surface orthogonal to the axial line N. Inaddition, the boss part 21 c only needs to be coupled with the springmember 23, and the boss part 21 c and the spring member 23 are onlyrequired to be at least fitted to each other such as being coupled byforming a groove that conforms with the spring member 23 in the bosspart 21 c besides press fitting.

The tip part 21 a has a crown shape with a plurality of claw parts. Theclaw parts project, for example, in the same pyramid shape as oneanother. Besides the crown shape, the tip shape of the tip part 21 a mayhave a conical shape, a planar shape, or a flat plate shape.

With regard to the flange part 21 b, an end part on the opposite side tothe side continuous to the tip part 21 a has a tapered shape. If aportion of the flange part 21 b is housed in the pipe member 22 at thetime of arrangement on the probe holder 3, or if a portion of the flangepart 21 b is housed in the pipe member 22 when a load other than gravityforce is not applied, as in the case of the first embodiment, a taperedshape may not be provided.

The pipe member 22 has a bottomed cylindrical shape. The pipe member 22includes a tip part 22 a having a sharp end abutting on the electrodeformed on the circuit board 200, a cylindrical part 22 b having acylindrical shape that extends from the base end of the tip part 22 a,and a flange part 22 c that projects from the outer surface of thecylindrical part 22 b.

The tip part 22 a becomes thinner toward the tip.

The diameter of the outer circumference of the cylindrical part 22 b is,for example, 0.4 mm or larger and 0.65 mm or smaller. In addition, thediameter of the inner circumference of the cylindrical part 22 b isuniform, and is equal to or larger than the diameter of the flange part21 b. The “equal” mentioned here includes manufacturing errors, andtolerance including a diameter in which the flange part 21 b isslidable.

The flange part 22 c has a tapered shape in which the projection lengthbecomes shorter from the tip part 22 a side to the opposite side.

The spring member 23 is made by, for example, winding one and the samewire material. The spring member 23 includes a rough wound part 23 athat is made by winding the wire material at a predetermined pitch, anda dense wound part 23 b that is provided at an end part on the sideabutting on the pipe member 22. With regard to the rough wound part 23a, a gap Ds of the wire materials adjacent to each other in the axialline N direction has a previously set length. With regard to the densewound part 23 b, the wire materials adjacent to each other in the axialline N direction are in contact with each other. The diameter of theouter circumference of the rough wound part 23 a is smaller than thediameter of the outer circumference of the dense wound part 23 b. Withregard to the spring member 23, for example, when a load other thangravity force is not applied, the diameter of the inner circumference ofthe rough wound part 23 a is equal to or smaller than the diameter ofthe boss part 21 c, and the diameter of the outer circumference of thedense wound part 23 b is equal to or larger than the diameter of theinner peripheral surface of the cylindrical part 22 b. An end part ofthe rough wound part 23 a is press-fitted into the boss part 21 c, andit abuts on the flange part 21 b. With regard to a portion that ispress-fitted into the boss part 21 c of the rough wound part 23 a, thepitch between the wire materials adjacent in the axial line N directionmay be small, or they may be in contact. Meanwhile, the dense wound part23 b is, for example, held by being press-fitted into the innerperipheral surface in the vicinity of the boundary between the tip part22 a and the cylindrical part 22 b. The plunger 21 and the spring member23 are joined by winding force of a spring and/or soldering. Inaddition, the pipe member 22 and the spring member 23 are joined bypressure welding and/or soldering.

In the first embodiment, the length of the spring member 23 of thecontact probe 2 in the natural state thereof in the central axis (axialline N) direction is smaller than the length of the cylindrical part 22b in the central axis (axial line N) direction (see FIG. 3). Thus, whenbeing arranged on the probe holder 3 with no load applied from thesemiconductor integrated circuit 100 and the circuit board 200, at leasta portion of the flange part 21 b is positioned inside the cylindricalpart 22 b in the probe 2 in the natural state thereof. The natural statementioned here refers to a state in which a load other than gravityforce is not applied.

Since the pipe member 22 is not swaged in the probe 2 according to thefirst embodiment, the probe 2 can be created even when the diameter isreduced.

The probe holder 3 is formed with an insulating material such as resin,machinable ceramic, or silicon, and is made by laminating a first member31 that is positioned on the upper surface side and a second member 32that is positioned on the lower surface side in FIG. 2. The same numberof holder holes 33, 34 for housing the probes 2 are formed in the firstmember 31 and the second member 32, and the holder holes 33, 34 forhousing the probes 2 are formed such that their axial lines match eachother. The positions at which the holder holes 33, 34 are formed aredetermined in accordance with a wiring pattern of the semiconductorintegrated circuit 100.

The holder holes 33, 34 both have a stepped hole shape having differentdiameters along the penetrating direction. That is to say, the holderhole 33 has a small-diameter part 33 a having an opening on the upperend surface of the probe holder 3, and a large-diameter part 33 b havinga larger diameter than the small-diameter part 33 a. Meanwhile, theholder hole 34 has a small-diameter part 34 a having an opening on thelower end surface of the probe holder 3, and a large-diameter part 34 bhaving a larger diameter than the small-diameter part 34 a. The shapesof these holder holes 33, 34 are determined in accordance with theconfiguration of the probe 2 to be housed. The flange part 21 b of theplunger 21 abuts on the boundary wall surface between the small-diameterpart 33 a and the large-diameter part 33 b of the holder hole 33 toprovide a function to prevent the probe 2 from falling off from theprobe holder 3. In addition, the flange part 22 c of the pipe member 22abuts on the boundary wall surface between the small-diameter part 34 aand the large-diameter part 34 b of the holder hole 34 to provide afunction to prevent the probe 2 from falling off from the probe holder3.

FIG. 4A and FIG. 4B are figures for explaining a contracted mode of thecontact probe according to the first embodiment of the presentinvention. FIG. 4A is a FIG. illustrating a state in which the pipemember 22 contacts the circuit board 200, and a load is not applied tothe tip part 21 a of the plunger 21. FIG. 4B is a figure illustrating atest state in which the semiconductor integrated circuit 100 is broughtinto contact with respect to the state illustrated in FIG. 4A.

When a load is not applied to the probe unit 1 from the semiconductorintegrated circuit 100 and the circuit board 200, as illustrated in FIG.2, in the probe 2, the flange part 21 b is locked on the step part ofthe holder hole 33 and the flange part 22 c is locked on the step partof the holder hole 34. At this time, a portion of the flange part 21 bis housed inside the cylindrical part 22 b. Thus, mismatch of the axialline of the plunger 21 and the axial line of the pipe member 22 can beprevented. Although FIG. 2 illustrates a state in which the probe 2 isheld by the probe holder 3, the length in the axial line N direction ofthe probe 2 that is removed from the probe holder 3 may become longerthan the length in the axial line N direction in the state of FIG. 2.

As illustrated in FIG. 4A, when the circuit board 200 is attached to theprobe unit 1, the pipe member 22 receives a load from the circuit board200, and is housed inside the probe holder 3. At this time, the end parton the opposite side to the tip part 22 a side of the cylindrical part22 b approaches the step part made by the small-diameter part 33 a andthe large-diameter part 33 b.

When the plunger 21 is brought into contact with the semiconductorintegrated circuit 100 in the state of FIG. 4A, as illustrated in FIG.4B, the plunger 21 receives a load from the semiconductor integratedcircuit 100, and enters the inside of the pipe member 22. At this time,a portion of the plunger 21 contacts the cylindrical part 22 b due to,for example, an inclination caused by the received load. A test signalthat is supplied from the circuit board 200 to the semiconductorintegrated circuit 100 at the time of test on the semiconductorintegrated circuit 100 as illustrated in FIG. 4B, reaches the connectionelectrode of the semiconductor integrated circuit 100 from the electrodeof the circuit board 200 via the pipe member 22 and the plunger 21 ofthe probe 2. In this manner, since conduction is performed via theplunger 21 and the pipe member 22 in the probe 2, a conduction path ofthe electrical signal can be minimized.

According to the first embodiment mentioned above, in the probe 2including the plunger 21, the pipe member 22, and the spring member 23,the spring member 23 is arranged inside the cylindrical part 22 b havinga uniform diameter, and the spring member 23 is coupled with the plunger21. Thus, the probe 2 can be created without requiring swaging of thepipe member 22, and the reduction of a diameter can be realized in theconfiguration using the pipe member. In the probe 2 according to thefirst embodiment, one end part of the spring member 23 holds the bosspart 21 c, and the other end part is held by the cylindrical part 22 b.Thus, the spring member 23 prevents the plunger 21 from being detachedfrom the pipe member 22. Meanwhile, in a configuration of creating aprobe by swaging a pipe member as in conventional techniques, creationmay not be possible since swaging is difficult if the diameter of thepipe member is about 0.4 mm.

First Modification of First Embodiment

FIG. 5 is a sectional view illustrating a configuration of a chief partof a contact probe according to a first modification of the firstembodiment of the present invention. The first embodiment mentionedabove describes the tip part 22 a becoming thinner toward its tip.However, it is not limited thereto. In order to increase the strength ofthe tip part of the pipe member 22, a thicker thickness is preferable.For example, the thickness of the tip may be made thick as in a tip part22 d illustrated in FIG. 5 by cutting with a sweep cut drill.Furthermore, the shape of the tip part may have a crown shape, a columnshape, or a cylindrical shapes besides a pyramid shape as illustrated inFIG. 2 and FIG. 5. A through hole that penetrates in the axial line Ndirection may also be formed at the tip of the tip part 22 a.

Second Modification of First Embodiment

FIG. 6 is a partial sectional view illustrating a configuration of achief part of a probe unit according to a second modification of thefirst embodiment of the present invention. FIG. 7 is a partial sectionalview illustrating a configuration of a contact probe according to thesecond modification of the first embodiment of the present invention. Aprobe 2A illustrated in FIG. 7 is in a state in which a load other thangravity force is not applied from the outside. In the first embodimentmentioned above, when a load from the semiconductor integrated circuit100 and the circuit board 200 is not applied to the probe unit 1, aportion of the flange part 21 b of the probe 2 is housed inside thecylindrical part 22 b. However, it is not limited thereto. For example,as in the case of the probe 2A illustrated in FIG. 6, when a load fromthe semiconductor integrated circuit 100 and the circuit board 200 isnot applied to the probe unit 1, the flange part 21 b may be positionedoutside the pipe member. The probe 2A includes a pipe member 22A insteadof the pipe member 22 in the probe 2 mentioned above. The pipe member22A includes a cylindrical part 22 e instead of the cylindrical part 22b of the pipe member 22. The length of the cylindrical part 22 e in theaxial line direction is shorter than that of the cylindrical part 22 b.

In the second modification, the length of the spring member 23 of thecontact probe 2A in the natural state thereof in the central axis (axialline N) direction is made longer than the length of the cylindrical part22 e in the central axis (axial line N) direction (see FIG. 7). Thus,when being arranged on the probe holder 3 with no load applied from thesemiconductor integrated circuit 100 and the circuit board 200, theflange part 21 b is positioned outside the cylindrical part 22 e in theprobe 2A in the natural state thereof. In this case, the plunger 21 cansmoothly advance into the pipe member 22A by shaping the end part on theopposite side to the tip part 21 a side of the flange part 21 b in atapered shape.

Third Modification of First Embodiment

FIG. 8 is a partial sectional view illustrating a configuration of achief part of a probe unit according to a third modification of thefirst embodiment of the present invention. A probe 2B according to thethird modification includes a pipe member 22B instead of the pipe member22 of the probe 2 mentioned above. The pipe member 22B includes a secondflange part 22 f in addition to the configuration of the pipe member 22mentioned above. The second flange part 22 f is provided at the end partof the cylindrical part 22 b that is on the opposite side of the sidecontinuous to the tip part. 22 a. In this manner, when the probe 2B ishoused in the holder holes 33, 34, an inclination of the probe 2B can besuppressed.

Fourth Modification of First Embodiment

FIG. 9 is a partial sectional view illustrating a configuration of achief part of a probe unit according to a fourth modification of thefirst embodiment of the present invention. In the first embodimentmentioned above, the probe holder 3 has the first member 31 in which theholder hole 33 having a stepped hole shape is formed, and the secondmember 32 in which the holder hole 34 having a stepped shape is formed.However, it is not limited thereto. As illustrated in FIG. 9, it is alsoapplicable to a probe holder 3A that includes a first member 35 in whicha plurality of holder holes 37 having stepped shapes are formed, and asecond member 36 in which a plurality of holder holes 38 having uniformdiameters are formed. The holder holes 37, 38 for housing the probes 2are formed such that their axial lines match each other.

The holder hole 37 has a stepped hole shape with varying diameters alongthe penetrating direction. Specifically, the holder hole 37 has asmall-diameter part 37 a having an opening on the lower end surface ofthe probe holder 3, and a large-diameter part 37 b having a largerdiameter than the small-diameter part 37 a. The holder hole 38 has adiameter that is smaller than the large-diameter part 37 b and largerthan the tip part 21 a.

The flange part 21 b of the plunger 21 abuts on the boundary wallsurface between the large-diameter part 37 b of the holder hole 37 andthe holder hole 38 to provide a function to prevent the probe 2 fromfalling off from the probe holder 3. In addition, the flange part 22 cof the pipe member 22 abuts on the boundary wall surface between thesmall-diameter part 37 a and the large-diameter part 37 b of the holderhole 37 to provide a function to prevent the probe 2 from falling offfrom the probe holder 3.

Fifth Modification of First Embodiment

FIG. 10 is a partial sectional view illustrating a configuration of achief part of a probe unit according to a fifth modification of thefirst embodiment of the present invention. In the first embodimentmentioned above, the probe holder 3 includes the first member 31 inwhich the holder hole 33 having a stepped shape is formed, and thesecond member 32 in which the holder hole 34 having a stepped shape isformed. However, it is not limited thereto. As illustrated in FIG. 10,it is also applicable to a probe holder 3B that is made of a singleplate.

The probe holder 3B is formed with an elastically deformable insulatingmaterial such as resin or silicon. The probe holder 3B has a pluralityof holder holes 39 for housing the probes 2. The positions at which theholder holes 39 are formed are determined in accordance with a wiringpattern of the semiconductor integrated circuit 100.

The holder hole 39 has a stepped hole shape with varying diametersalong, the penetrating direction. Specifically, the holder hole 39 has afirst small-diameter part 39 a having an opening on the upper endsurface of the probe holder 3B, a large-diameter part 39 b having alarger diameter than the first small-diameter part 39 a, and a secondsmall-diameter part 39 c having an opening on the lower end surface ofthe probe holder 3. The diameter of the second small-diameter part 39 cIs larger than the diameter of the outer circumference of thecylindrical part 22 b, and is smaller than the maximum diameter of theflange part 22 c. The shapes of the holder holes 39 are determined inaccordance with the configuration of the probes 2 to be housed. Theflange part 21 b of the plunger 21 abuts on the boundary wall surfacebetween the first small-diameter part 39 a and the large-diameter part39 b to provide a function to prevent the probe 2 from falling off fromthe probe holder 3B. In addition, the flange part 22 c of the pipemember 22 abuts on the boundary wall surface between the large-diameterpart 39 b and the second small-diameter part 39 c, to provide a functionto prevent the probe 2 from falling off from the probe holder 3B.

When arranged in the probe holder 3B, the probe 2 is inserted into thesecond small-diameter part 39 c from the plunger 21 side. At this time,the second small-diameter part 39 c deforms due to press fit of theflange part 22 c, and then returns to its original shape. In thismanner, the second small-diameter part 39 c is engaged with the flangepart 22 c while the probe 2 is arranged inside the holder hole 39,thereby providing a function to prevent the probe 2 from falling offfrom the probe holder 3B.

In addition, since the flange part 22 c has a tapered shape in the fifthmodification, insertability into the holder hole 39, especially thesecond small-diameter part 39 c, can be improved.

Sixth Modification of First Embodiment

FIG. 11 is a partial sectional view illustrating a configuration of acontact probe according to a sixth modification of the first embodimentof the present invention. A probe 2C illustrated in FIG. 11 is in astate in which a load other than gravity force is not applied from theoutside. The probe 2C according to the sixth modification includes apipe member 22C instead of the pipe member 22 of the probe 2 mentionedabove. The pipe member 22C is such a member having a slit 22 g in thecylindrical part 22 b of the pipe member 22 mentioned above. The slit 22g is provided from the end part of the cylindrical part 22 b that is onthe opposite side to the side continuous to the tip part 22 a, to theend part of the flange part 22 c on the tip part 22 a side. In thismanner, for example, at the time of insertion of the probe 2C into theholder hole 39 of the probe holder 3B shown in the fifth modification,when the cylindrical part 22 b and the flange part 22 c come near thesecond small-diameter part 39 c, the outer diameters of the cylindricalpart 22 b and the flange part 22 c will be reduced. Due to reduction ofthe outer diameter of the pipe member 22C, the probe can be insertedinto the holder hole 39 more easily. The length of the spring member 23of the probe 2C in the natural state thereof in the central axis (axialline N) direction is preferably made larger than the length of thecylindrical part 22 b in the central axis (axial line N) direction inorder to reduce the diameter of the pipe member 22C.

(Seventh modification of first embodiment)

FIG. 12 is a partial sectional view illustrating a configuration of achief part of a probe unit according to a seventh modification of thefirst embodiment of the present invention. A probe 2D according to theseventh modification includes a plunger 21A instead of the plunger 21,and further includes a sleeve 24, as compared with the configuration ofthe probe 2 mentioned above. The rough wound part 23 a of the springmember 23 and the small-diameter part 33 a of the probe holder 3 havesmall diameters so as to conform with the plunger 21A.

The plunger 21A is such a plunger in which the outer diameter of theplunger 21 mentioned above is made small. The plunger 21A includes a tippart 21 e having a crown shape, a flange part 21 f having a largerdiameter than the diameter of the tip part 21 e, a boss part 21 g intowhich an end part of the spring member 23 is press-fitted, extending tothe opposite side to the tip part 21 e with respect to the flange part21 f and having a smaller diameter than the flange part 21 f does, and abase end part 21 h extending to the opposite side to the flange part 21f with respect to the boss part 21 g and having a diameter slightlysmaller than that of the boss part 21 g. The plunger 21A is movable inthe axial line direction with expansion/contraction action of the springmember 23, and is biased in the direction of the semiconductorintegrated circuit 100 with elastic force of the spring member 23,thereby contacting the electrode of the semiconductor integrated circuit100.

The sleeve 24 is formed with a conductive material, and it has acylindrical shape. The flange part. 21 f is press-fitted into the sleeve24, and the outer surface of the sleeve 24 slidably contacts thecylindrical part 22 b. At this time, the end part of the sleeve 24 onthe tip part 21 e side is positioned at the same position as the surfaceof the flange part 21 f on the tip part 21 e side, or is positioned onthe base end side of that position. In addition, the sleeve 24 onlyneeds to be coupled with the flange part 21 f, and the sleeve 24 and theflange part 21 f are only required to be at least fitted with each othersuch as being coupled by forming grooves that are fittable with eachother in the inner circumference of the sleeve 24 and the outercircumference of the flange part 21 f besides press fitting.

The flange part 21 f of the plunger 21A abuts on the boundary wallsurface between the small-diameter part 33 a and the large-diameter part33 b of the holder hole 33 to provide a function to prevent the probe 2Afrom falling off from the probe holder 3.

When a load from the semiconductor integrated circuit 100 and thecircuit board 200 is applied, the probe 2D mentioned above operates inthe same manner as the probe 2 illustrated in FIG. 4A and FIG. 4B. Whena load is applied to the probe 2D from the outside, the plunger 21A andthe sleeve 24 integrally move, and the sleeve 24 slides on thecylindrical part 22 b. A test signal that is supplied from the circuitboard 200 to the semiconductor integrated circuit 100 at the time oftest on the semiconductor integrated circuit 100 reaches the connectionelectrode of the semiconductor integrated circuit 100 from the electrodeof the circuit board 200 via the pipe member 22, the sleeve 24, and theplunger 21A of the probe 2D. In this manner, since conduction is madevia the plunger 21A, the sleeve 24, and the pipe member 22 in the probe2D, a conduction path of the electrical signal can be minimized. Inaddition, also in the seventh modification, the probe 2D can be createdwithout requiring swaging of the pipe member 22, and a diameter can bereduced in the configuration using the pipe member.

The spring member 23 of the seventh modification may have aconfiguration in which the rough wound part 23 a is coupled with thesleeve 24, instead of a configuration in which the rough wound part 23 ais coupled with the boss part 21 g.

Furthermore, in the seventh modification, a flange may be provided inthe outer circumference of the sleeve 24, and the flange may be causedto abut on the step part of the holder hole 33, so as to secure afunction to prevent the probe 2A from falling off from the probe holder3.

Second Embodiment

FIG. 13 is a partial sectional-view illustrating a configuration of achief part of a probe unit according to a second embodiment of thepresent invention. In the first embodiment mentioned above, the probe 2includes the plunger 21, the pipe member 22, and the spring member 23.However, it is not limited thereto. In the present second embodiment, aprobe 2E includes two pipe members and a spring member.

The probe 2E includes a first pipe member 25, the pipe member 22 that isa second pipe member (hereinafter referred to as the second pipe member22), and a spring member 23A.

The first pipe member 25 has a bottomed cylindrical shape. The firstpipe member 25 includes a tip part 25 a having a sharp end that abuts onthe electrode formed on the semiconductor integrated circuit 100, acylindrical part 25 b having a cylindrical shape that extends from thebase end of the tip part 25 a, and a flange part 25 c that projects fromthe outer surface of the cylindrical part 25 b.

The trip part 25 a has, for example, one and the same thickness. Thethickness may become thinner or thicker toward the tip.

The diameter of the outer circumference of the cylindrical part 25 b issmaller than the diameter of the inner circumference of the cylindricalpart 22 b.

The flange part 25 c has a tapered shape in which the projection lengthbecomes shorter from the tip part 25 a side toward the opposite side.The maximum diameter of the flange mart 25 c is equal to or smaller thanthe diameter of the inner circumference of the cylindrical part 22 b.

The spring member 23A is positioned in a hollow space that is formedwith the first pipe member 25 and the second pipe member 22. Inaddition, the spring member 23A includes a first dense wound part 23 cthat is provided at the end part on the side abutting on the first pipemember 25, a rough wound part 23 d that is wound at a predeterminedpitch, and the dense wound part 23 b that is a second dense wound partprovided at the end part on the side abutting on the second pipe member22 (hereinafter referred to as the second dense wound part 23 b). Thediameter of the outer circumference of the first dense wound part 23 cis smaller than the diameter of the outer circumference of the seconddense wound part 23 b. The diameter of the outer circumference of therough wound part 23 d is smaller than the diameter of the outercircumference of the first dense wound part 23 c or the second densewound part 23 b.

The spring member 23A is made by, for example, winding one and the samewire material, and when a load other than gravity force has not beenapplied, the diameter of the outer circumference of the first densewound part 23 c is equal to or larger than the diameter of the innercircumference of the cylindrical part 25 b. The first dense wound part23 c is, for example, press-fitted into the inner peripheral surface inthe vicinity of the boundary between the tip part 25 a and thecylindrical part 25 b. Meanwhile, the second dense wound part 23 b is,for example, press-fitted into the inner peripheral surface in thevicinity of the boundary between the tip part 22 a and the cylindricalpart 22 b. The first pipe member 25 and the spring member 23A are joinedby pressure welding and/or soldering. In addition, the second pipemember 22 and the spring member 23A are joined by pressure weldingand/or soldering.

When a load from the semiconductor integrated circuit 100 and thecircuit board 200 is applied, the probe 2E mentioned above operates inthe same manner as the probe 2 illustrated in FIG. 4A and FIG. 4B A testsignal that is supplied from the circuit board 200 to the semiconductorintegrated circuit 100 at the time of test on the semiconductorintegrated circuit 100 reaches the connection electrode of thesemiconductor integrated circuit 100 from the electrode of the circuitboard 200 via the second pipe member 22 and the first pipe member 25 ofthe probe 2E. In this manner, since conduction is made through the firstpipe member 25 and the second pipe member 22 in the probe 2E, aconduction path of the electrical signal can be minimized.

According to the second embodiment mentioned above, in the probe 2Eincluding the first pipe member 25, the second pipe member 22, and thespring member 23A, the spring member 23A is arranged inside thecylindrical part 22 b having a uniform diameter, and the spring member23A is coupled with the first pipe member 25. Thus, the probe 2E can becreated without requiring swaging of the second pipe member 22, and adiameter can be reduced in the configuration using the pipe member. Inthe probe 2E according to the second embodiment, one end part of thespring member 23A is held by the cylindrical part 25 b, and the otherend part is held by the cylindrical part 22 b. Thus, the spring member23A prevents the first pipe member 25 from being detached from thesecond pipe member 22.

INDUSTRIAL APPLICABILITY

As described above, a contact probe and a probe unit according to thepresent invention are suitable in reducing a diameter in a configurationusing a pipe member.

REFERENCE SIGNS LIST

1 probe unit

2, 2A, 2B, 2C, 2D, 2E contact probe (probe)

3, 3A, 3B probe holder

21 plunger

21 a, 22 a, 22 d, 24 a tip part

21 b, 22 c, 24 c flange part

21 c boss part

21 d base end part

22, 22A, 22B, 22C pipe member

22 b, 24 b, 22 e cylindrical part

22 f second flange part

22 g slit

23, 23A spring member

23 a, 23 d rough wound part

23 b dense wound part

23 c first dense wound part

24 sleeve

25 first pipe member

31, 35 first member

32, 36 second member

33, 34, 37, 38, 39 holder hole

33 a, 34 a, 37 a small-diameter part

33 b, 34 b, 37 b, 39 b large-diameter part

39 a first small-diameter part.

39 c second small-diameter part

100 semiconductor integrated circuit

200 circuit board

The invention claimed is:
 1. A contact probe that is conductive andcapable of expanding/contracting along an axial line direction, thecontact probe comprising: a first contact member configured to contactone contact target; a second contact member configured to contactanother contact target, and to house at least a portion of the firstcontact member; and a spring member configured to couple the firstcontact member and the second contact member in a manner capable ofexpansion/contraction with both end parts of the spring member, whereinthe spring member is wound in a helical shape, and at least a diameterof an outer circumference in one of the end parts held by the secondcontact member is larger than diameters of other portions, and adiameter of an inner circumference of an end part of the second contactmember on a side housing the first contact member is equal to or largerthan a maximum diameter of the first contact member, wherein the firstcontact member comprises: a first tip part configured to contact the onecontact target; a first flange part provided at a base end of the firsttip part; and a boss part configured to couple with the spring member byfitting into the spring member, and the second contact member comprises:a second tip part configured to contact the other contact target, acylindrical part extending from the second tip part and having acylindrical shape with an inner circumference having a uniform diameter,the cylindrical part being engaged with at least a portion of the springmember, the portion of the spring member that is engaged with thecylindrical part having a diameter larger than the other portion of thespring member, the entire spring member being configured to be housed inthe cylindrical part when the spring member is contracted; and a secondflange part provided in an outer circumference of the cylindrical part.2. The contact probe according to claim 1, wherein a length of thespring member in a natural state thereof in the axial line direction issmaller than a length of the cylindrical part in the axial linedirection.
 3. The contact probe according to claim 1, wherein a lengthof the spring member in a natural state thereof in the axial linedirection is larger than a length of the cylindrical part in the axialline direction.
 4. The contact probe according to claim 1, furthercomprising a sleeve into which the first flange part is fit, an outersurface of the sleeve slidably contacting the cylindrical part.
 5. Thecontact probe according to claim 1, wherein the spring member comprises:a rough wound part wound with a previously set gap, an innercircumference of the rough wound part contacting the first contactmember; and a dense wound part extending from the rough wound part, anouter circumference of the dense part contacting the cylindrical part,and a diameter of the dense wound part is larger than a diameter of therough wound part.
 6. The contact probe according to claim 1, wherein thefirst contact member comprises: a first tip part configured to contactthe one contact target; a first cylindrical part extending from thefirst tip part in a cylindrical shape; and a first flange part providedin an outer circumference of the first cylindrical part, the secondcontact member comprises: a second tip part configured to contact theother contact target; a second cylindrical part extending from thesecond tip part and having a cylindrical shape with an innercircumference having a uniform diameter; and a second flange partprovided in an outer circumference of the second cylindrical part, andthe spring member is positioned in a hollow space formed with the firstand the second cylindrical parts.
 7. The contact probe according toclaim 6, wherein the spring member comprises: a first dense wound part,an outer circumference of the first dense wound part contacting thefirst cylindrical part; a rough wound part wound with a previously setgap, the rough wound part extending from the first dense wound part; anda second dense wound part, an outer circumference that of the seconddense wound part contacting the second cylindrical part, and the seconddense wound part being provided at an end part of the rough wound parton an opposite side of the first dense wound part, a diameter of thefirst dense wound part is smaller than a diameter of the second densewound part, and a diameter of the rough wound part is smaller than thediameter of the first dense wound part.
 8. The contact probe accordingto claim 1, wherein an end part of the first flange part on an oppositeside to a side continuous to the first tip part has a tapered shape. 9.A probe unit comprising: contact probes, each of which is conductive,and capable of expanding/contracting along an axial line direction, eachof the contact probes comprising: a first contact member configured tocontact one contact target; a second contact member configured tocontact another contact target, and to house at least a portion of thefirst contact member; and a spring member wound in a helical shape andconfigured to couple the first contact member and the second contactmember in a manner capable of expansion/contraction with both end partsof the spring member, wherein a diameter of an outer circumference inthe end part held by at least the second contact member being largerthan diameters of other portions, and a diameter of an innercircumference of an end part of the second contact member on a sidehousing the first contact member is equal to or larger than a maximumdiameter of the first contact member; and a probe holder includingholder holes configured to hold the respective contact probes, whereinthe first contact member comprises: a first tip part configured tocontact the one contact target; a first flange part provided at a baseend of the first tip part; and a boss part configured to couple with thespring member by fitting into the spring member, and the second contactmember comprises: a second tip part configured to contact the othercontact target, a cylindrical part extending from the second tip partand having a cylindrical shape with an inner circumference having auniform diameter, the cylindrical part being engaged with at least aportion of the spring member, the portion of the spring member that isengaged with the cylindrical part having a diameter larger than theother portion of the spring member, the entire spring member beingconfigured to be housed in the cylindrical part when the spring memberis contracted; and a second flange part provided in an outercircumference of the cylindrical part.
 10. The probe unit according toclaim 9, wherein the first contact member comprises a flange part havinga maximum diameter of the first contact member, and when the contactprobe is held by the probe holder, at least a portion of the flange partis positioned inside the second contact member.
 11. The probe unitaccording to claim 9, wherein the first contact member comprises aflange part having a maximum diameter of the first contact member, andwhen the contact probe is held by the probe holder, the flange part ispositioned outside the second contact member.
 12. The probe unitaccording to claim 9, wherein the probe holder is made of a singleplate.
 13. The probe unit according to claim 12, wherein the secondcontact member comprises: a tip part configured to contact the othercontact target; a cylindrical part extending from the tip part andhaving a cylindrical shape with an inner circumference having a uniformdiameter; and a flange part provided in an outer circumference of thecylindrical part, and a slit extending from the end part of thecylindrical part on an opposite side of the tip part is formed in thecylindrical part.
 14. A contact probe that is conductive and capable ofexpanding/contracting along an axial line direction, the contact probecomprising: a first contact member configured to contact one contacttarget; a second contact member configured to contact another contacttarget, and to house at least a portion of the first contact member; anda spring member configured to couple the first contact member and thesecond contact member in a manner capable of expansion/contraction withboth end parts of the spring member, wherein the spring member is woundin a helical shape, and at least a diameter of an outer circumference inone of the end parts held by the second contact member is larger thandiameters of other portions, and a diameter of an inner circumference ofan end part of the second contact member on a side housing the firstcontact member is equal to or larger than a maximum diameter of thefirst contact member, wherein the spring member comprises: a first densewound part, an outer circumference of the first dense wound partcontacting a first cylindrical part of the first contact member; a roughwound part wound with a previously set gap, the rough wound partextending from the first dense wound part; and a second dense woundpart, an outer circumference that of the second dense wound partcontacting a second cylindrical part of the second contact member, andthe second dense wound part being provided at an end part of the roughwound part on an opposite side of the first dense wound part, a diameterof the first dense wound part is smaller than a diameter of the seconddense wound part, and a diameter of the rough wound part is smaller thanthe diameter of the first dense wound part.